It has recently been shown that a number of common human pathogens, including Enterococcus faecalis, Streptococcus pneumoniae and Staphylococcus aureus are dependent on enzymes in the mevalonate pathway for biosynthesis of IPP, including the central pathway enzyme HMG-CoA reductase. This raises the possibility that a targeted inhibitor of HMG-CoA reductase would be an anti-bacterial specific for these pathogens, with a unique point of attack that would leave this class of inhibitors unaffected by the resistance mechanisms that have developed against the more common cell-wall antagonists. This selective property would make mevalonate pathway inhibitors particularly attractive in burn unit or intensive care settings where sterilization of the normal bacterial flora make yeast over growth or colonization by resistant bacteria a common and severe complication of broad-spectrum antibiotic use. The goal of this proposal is to identify a set of molecular probes that selectively inhibit the activity of the Class II HMG-CoA reductase (HMGR) of pathogenic bacteria. This proposal seeks access to HTS resources provided by the Molecular Libraries Screening Center Network (MLSCN) where an HTS-ready assay can be employed to explore the differences in the structure activity relationships of the human and pathogenic bacterial HMGRs. A preliminary study using a spectrophotometric assay in high throughput format has demonstrated this assay is exceptionally robust, and identified seven compounds (0.18% hit rate) with significant inhibitory effects, and therefore is ready to be translated to a designated screening center. Secondary assays to be performed in the collaborating laboratories are proposed to confirm the potency and to further understand the molecular basis of the inhibition, including more detailed enzymology of the inhibitory effects selected compounds, bacterial toxicity assessments and detailed structural studies of these compounds in complexes with bacterial HMGRs. It has recently been shown that a number of common human pathogens, including Enterococcus faecalis, Streptococcus pneumoniae and Staphylococcus aureus are dependent on enzymes in the mevalonate pathway for biosynthesis of IPP, including the central pathway enzyme HMG-CoA reductase. This raises the possibility that a targeted inhibitor of HMG-CoA reductase would be an anti-bacterial specific for these pathogens, with a unique point of attack that would leave this class of inhibitors unaffected by the resistance mechanisms that have developed against the more common cell-wall antagonists. This selective property would make mevalonate pathway inhibitors particularly attractive in burn unit or intensive care settings where sterilization of the normal bacterial flora make yeast over growth or colonization by resistant bacteria a common and severe complication of broad-spectrum antibiotic use. [unreadable] [unreadable] [unreadable]